@TECHREPORT{dcgomes06VNRT,
  author = {Daniel Gomes and M{\'a}rio J. Silva},
  title = {The {V}iuva {N}egra web crawler},
  institution = {Department of Informatics, University of Lisbon},
  year = {2006},
  type = {DI/FCUL TR},
  number = {06--21},
  month = {November},
  url = {http://www.di.fc.ul.pt/tech-reports/06-21.pdf}
}